diff --git a/drover b/drover
index 0e7b1265f..12dc53e4e 100755
--- a/drover
+++ b/drover
@@ -22,5 +22,4 @@ then
   svn -q up "${base_dir}"
 fi
 
-exec python "${base_dir}/drover.py" "$@"
-
+PYTHONDONTWRITEBYTECODE=1 exec python "${base_dir}/drover.py" "$@"
diff --git a/drover.bat b/drover.bat
index 182da1075..7aa62468e 100644
--- a/drover.bat
+++ b/drover.bat
@@ -5,5 +5,5 @@
 
 setlocal
 set PATH=%~dp0svn;%PATH%
-
+set PYTHONDONTWRITEBYTECODE=1
 call python "%~dp0drover.py" %*
diff --git a/gcl b/gcl
index c0cface83..e48956de5 100755
--- a/gcl
+++ b/gcl
@@ -5,4 +5,4 @@
 
 base_dir=$(dirname "$0")
 
-exec python "$base_dir/gcl.py" "$@"
+PYTHONDONTWRITEBYTECODE=1 exec python "$base_dir/gcl.py" "$@"
diff --git a/gcl.bat b/gcl.bat
index 05c1735e4..786ceea06 100755
--- a/gcl.bat
+++ b/gcl.bat
@@ -2,4 +2,5 @@
 setlocal
 :: This is required with cygwin only.
 PATH=%~dp0;%PATH%
+set PYTHONDONTWRITEBYTECODE=1
 call python "%~dp0gcl.py" %*
diff --git a/gclient b/gclient
index 5d7422d86..bba81cff1 100755
--- a/gclient
+++ b/gclient
@@ -7,4 +7,4 @@ base_dir=$(dirname "$0")
 
 "$base_dir"/update_depot_tools
 
-exec python "$base_dir/gclient.py" "$@"
+PYTHONDONTWRITEBYTECODE=1 exec python "$base_dir/gclient.py" "$@"
diff --git a/git-cl b/git-cl
index 3c5457bbd..4f696f020 100755
--- a/git-cl
+++ b/git-cl
@@ -16,7 +16,7 @@ OUTPUT="$(uname | grep 'MINGW')"
 MINGW=$?
 
 if [ -d "$base_dir/python_bin" -a $MINGW = 0 ]; then
-  exec "$base_dir/python_bin/python.exe" "$base_dir"/git_cl.py "$@"
+  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/python_bin/python.exe" "$base_dir"/git_cl.py "$@"
 else
-  exec "$base_dir/git_cl.py" "$@"
+  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/git_cl.py" "$@"
 fi
diff --git a/git-try b/git-try
index fc6b3629f..39b94ce18 100755
--- a/git-try
+++ b/git-try
@@ -11,7 +11,7 @@ OUTPUT="$(uname | grep 'MINGW')"
 MINGW=$?
 
 if [ -d "$base_dir/python_bin" -a $MINGW = 0 ]; then
-  exec "$base_dir/python_bin/python.exe" "$base_dir"/git_try.py "$@"
+  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/python_bin/python.exe" "$base_dir"/git_try.py "$@"
 else
-  exec "$base_dir/git_try.py" "$@"
+  PYTHONDONTWRITEBYTECODE=1 exec "$base_dir/git_try.py" "$@"
 fi